panda_kinq

Well, my last thread died out and some new issues have popped up so I figured it's time to start another.

Original problems of major lack of power in the low end, very very rich fuel ratio, and glowing hot headers still exist. No idea what's causing it.

I drove it a little over 1k miles to get to my duty station (I'm in the Air Force) from San Diego to New Mexico. Since then, some new issues have popped up.

Something about the elevation/cold (4300ft asl, cold start outside temp is about 25-35F) is causing me to have some interesting starting issues and a SEVERE lack of power until it gets warm (I'd say I'm putting 50-75HP MAX to the rear wheels). When I start it in the morning (well, pretty much all the time) it'll crank over a few times (usually no more than 4 times) and then only hit 400 or so RPM, sound like it is about to choke out, then jump up to 1200 or so RPM. After a little while it will come down to about 800 RPM and just flutter up and down 100 or so RPM.

Another issue when it is cold started in the morning, going from a stop at a stop sign and then taking off, the engine will choke itself and stutter down to 200-400 RPM and give no power and then bump up and take off with very very little power. Once it hits 2-3k RPM it will get a little more power and make it to 30 mph or so and then we're good after that.

So, as for possible issues, I've been told by a mechanic that my MAF and O2 sensors look fine. I would like to actually test them, but don't really know how to.

EGR might have something to do with this, I unplugged the vacuum lines from the EGR valve and it seemed to drive a little bit easier. But, a check engine light never came on which I assumed was supposed to due to the EGR temp sensor always being cold. Then, one day, coming off a stop sign, all of the sudden the little power that was there suddenly dropped off and the CEL popped on. Barely had any juice, I was going like 5-10mph MAX at full throttle. Made it to a parking lot, hooked up the EGR and the CEL was gone and it drove as usual. Re-disconnected the EGR and the CEL didn't come on and it was just the same. The CEL and power problem has not happened again.

So I'm thinking a bad sensor of some kind or a bad ECU is causing the rich running/general lack of power/and glowing headers. Any idea how to test those out? Now as for whats going on with the EGR, I have no idea and no idea what effect that is having on the truck. I have no idea what is causing the cold start issues and start from a stop issues.

Ideas on what to check/how to check?

Oh, and power steering pump squeals like a beast when it's cold.

EDIT: Oh, another symptom was a glowing CAT, but since I'm no longer in CA, I cut the CAT off and replaced it with straight pipe. So I really just masked the issue ha ha.

mtrdrms

EGR won't cause that type of problem. You say there is not CEL now? How about the basics, have you checked the timing? Done a basic tuneup? What does the oil look like? Any headgasket issues? How do you know its running rich?

panda_kinq

Nope, no CEL. Timing etc... was all checked by 2 mechanics and is fine. Every response I've gotten so far is that everything is fine, it's probably the computer, take it to a dealership.

Any way to diagnose a bad ECU?

Oil looks fine, it doesn't burn oil, doesn't leak, nothing like that.

Headgasket was done at 170K, has 196K now.

I base the idea of running rich off of the glowing cat and headers and the fact that I can smell real rich fuel in the exhaust and in the cabin when driving. Running rich would also account for the overall lack of power.